CN110754110A

CN110754110A - Method and apparatus for controlling packet transmission

Info

Publication number: CN110754110A
Application number: CN201880040175.1A
Authority: CN
Inventors: 白祥圭; A.阿吉瓦尔; 姜贤贞
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2017-06-15
Filing date: 2018-06-12
Publication date: 2020-02-04
Anticipated expiration: 2038-06-12
Also published as: KR20180136898A; US11375427B2; WO2018230920A1; KR102626164B1; EP3627882A4; US11722942B2; EP3627882A1; CN110754110B; US20200120569A1; US20220361074A1

Abstract

An object of the present invention is to provide a method for improving data transmission efficiency when packet duplication is performed. The method for a terminal in a wireless communication system according to the present invention comprises the steps of: performing Protocol Data Convergence Protocol (PDCP) duplication in which the same PDCP Protocol Data Unit (PDU) is transmitted to the base station through each of the first and second logical channels; retransmitting the PDCP PDU to the base station when receiving a request for retransmission of the PDCP PDU that has been transmitted through the second logical channel from the base station; and receiving information indicating deactivation of PDCP duplication from the base station when the PDCP PDUs have been retransmitted for a predetermined number of times or more.

Description

Method and apparatus for controlling packet transmission

Technical Field

The present disclosure relates to a method and apparatus for controlling packet transmission in a mobile communication system.

Background

In order to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts have been made to develop improved 5G communication systems or pre-5G (pre-5G) communication systems. Therefore, the 5G communication system or the pre-5G communication system is referred to as a super 4G network communication system or a post-LTE system.

In order to achieve a high data transmission rate, it is being considered to implement a 5G communication system in a millimeter wave band (for example, 60GHz band). In a 5G communication system, technologies such as beamforming, massive multiple-Input multiple-Output (MIMO), Full-Dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technologies are under discussion, with the goal of mitigating propagation path loss and increasing propagation transmission distance in the millimeter wave band.

Further, in 5G communication systems, techniques such as evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense networks, Device-to-Device communication (D2D), wireless backhaul, mobile networks, cooperative communication, Coordinated Multi-Point (CoMP), and receive interference cancellation have been developed to improve system networks.

In addition, the 5G system also develops Advanced Coding Modulation (ACM) schemes such as hybrid-Shift Keying (FSK) and Quadrature Amplitude Modulation (QAM) Modulation and Sliding Window Superposition Coding (SWSC), and Advanced Access techniques such as filterbank multicarrier (FBMC), Non-Orthogonal Multiple Access (NOMA), and Sparse Code Multiple Access (SCMA).

Disclosure of Invention

Technical problem

The present disclosure provides a method for efficiently managing a radio link in the case where the number of retransmissions reaches a maximum when packet duplication (duplication) is performed.

Also, the present disclosure provides a method of improving data transmission efficiency when packet duplication is performed.

Also, the present disclosure defines a method for generating a security key in a Non-dependent (NSA) structure.

Also, the present disclosure defines a method for performing integrity checking in a split bearer.

Technical scheme

In order to solve the above problem, a method of a terminal of a wireless communication system according to one embodiment of the present disclosure may include: executing Protocol Data Convergence Protocol (PDCP) replication to transmit a same PDCP Protocol Data Unit (PDU) to the base station through the first and second logical channels; retransmitting the PDCP PDU to the base station if a request for retransmission of the PDCP PDU transmitted through the second logical channel is received from the base station; and receiving information indicating deactivation of PDCP duplication from the base station if the number of retransmission of PDCP PDUs becomes equal to or greater than a preconfigured number.

The method of a base station in a wireless communication system according to one embodiment of the present disclosure may include: transmitting a message to a terminal, wherein the message indicates activation of PDCP duplication for transmitting a same Protocol Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) through a first logical channel and a second logical channel; requesting retransmission of the PDCP PDU transmitted through the second logical channel to the terminal; receiving a report from the terminal, wherein the report provides notification that the number of retransmissions of the PDCP PDU is equal to or greater than a preconfigured number; and transmitting information indicating deactivation of PDCP duplication to the terminal.

A terminal in a wireless communication system according to one embodiment of the present disclosure may include: a transceiver; and a controller configured to perform PDCP duplication for transmitting a same Protocol Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) to the base station through the first and second logical channels, control the transceiver to retransmit the PDCP PDU to the base station if a request for retransmission of the PDCP PDU transmitted through the second logical channel is received from the base station, and control the transceiver to receive information indicating deactivation of the PDCP duplication from the base station if a number of PDCP PDU retransmissions becomes equal to or greater than a preconfigured number.

A base station in a wireless communication system according to one embodiment of the present disclosure may include: a transceiver; and a controller configured to transmit a message to the terminal, wherein the message indicates activation of PDCP duplication for transmitting a same Protocol Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) through the first and second logical channels, request retransmission of the PDCP PDU transmitted through the second logical channel to the terminal, receive a report from the terminal, wherein the report provides notification that a number of retransmissions of the PDCP PDU is equal to or greater than a preconfigured number, and control the transceiver to transmit information indicating deactivation of PDCP duplication to the terminal.

Advantageous effects

According to the embodiments of the present disclosure, it is possible to efficiently manage a radio link and improve transmission efficiency during duplicate transmission of a packet.

According to another embodiment of the present disclosure, it is possible to generate various security keys in the NSA architecture.

According to another embodiment of the present disclosure, it is possible to perform integrity checking in a split bearer according to a security attack.

Drawings

Fig. 1 illustrates a structure in which packet replication is performed in carrier aggregation (hereinafter, referred to as ca (carrieraggrregeration)), according to one embodiment of the present disclosure.

Fig. 2 illustrates operations in a case where the number of RLC retransmissions reaches a maximum according to one embodiment of the present disclosure.

Fig. 3 illustrates operations in a case where the number of RLC retransmissions reaches a maximum according to one embodiment of the present disclosure.

Fig. 4 illustrates an operation in a case where RLF occurs in a certain logical channel according to one embodiment of the present disclosure.

Fig. 5 illustrates an operation in a case where the number of RLC retransmissions reaches a maximum according to one embodiment of the present disclosure.

Fig. 6 illustrates operations in a case where the number of RLC retransmissions reaches a maximum according to one embodiment of the present disclosure.

Fig. 7 illustrates changes in packet transmission structure with duplicate packet activation and deactivation according to one embodiment of the disclosure.

Fig. 8 illustrates operations with duplicate packet activation according to one embodiment of the present disclosure.

Fig. 9 illustrates operations with duplicate packet activation according to one embodiment of the present disclosure.

Fig. 10 illustrates operation with SCell deactivated according to one embodiment of the disclosure.

Fig. 11 illustrates a protocol stack structure in an NSA structure according to one embodiment of the present disclosure.

Fig. 12 illustrates a base station transmitting PDCP-Config (PDCP configuration) to a terminal according to one embodiment of the present disclosure.

Fig. 13 shows a terminal implementation structure according to an embodiment of the present disclosure.

Fig. 14 illustrates a method for generating a security key in an NSA architecture according to one embodiment of the present disclosure.

Fig. 15 illustrates an example of an integrity check that may be determined to be a security attack according to one embodiment of the present disclosure.

Figure 16 illustrates an integrity check operation in a bearer in which duplicate packet transmission is not allowed, according to one embodiment of the disclosure.

Fig. 17 illustrates an integrity check operation in a bearer in which duplicate packet transmission is allowed, according to one embodiment of the disclosure.

Fig. 18 shows a terminal structure according to an embodiment of the present disclosure.

Fig. 19 shows a base station structure according to one embodiment of the present disclosure.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, a detailed description of known functions or configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure unclear. Terms to be described below are terms defined in consideration of functions in the present disclosure, and may be different according to a user, a user intention, or a habit. Therefore, the definition of the terms should be based on the contents of the entire specification.

Advantages and features of the present disclosure and the manner of attaining them will become apparent by reference to the following detailed description of embodiments taken in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but may be embodied in various different forms. The following examples are provided solely for the purpose of complete disclosure and to inform those skilled in the art of the scope of the disclosure, and the disclosure is to be limited only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements.

Fig. 1 shows a structure in which duplicate packet transmission is performed in carrier aggregation (hereinafter referred to as CA).

"duplicate packet transmission" means that one Packet Data Convergence Protocol (PDCP) device 100 duplicates packets (PDCP Protocol Data Units (PDUs)) and then transfers data to two or more Radio Link Control (RLC)

devices

101 and 102 to independently perform transmission. One RLC device corresponds to one logical channel.

In order to efficiently perform duplicate packet transmission in a CA environment, it is necessary to map logical channels and cells. In other words, the logical channel requirements limit the cells to which data can be transmitted. Fig. 1 is an example illustrating that logical channel 1101 may transmit data to primary cell (PCell)111, secondary cell (SCell) 1112, and SCell 2113, and logical channel 2 may transmit data to SCell 3114 and SCell 4115. A cell is also called a component carrier (hereinafter, referred to as cc (component carrier)).

In the case where transmission is not completed even if a certain packet has been maximally retransmitted from the RLC device (when the retxcount value reaches maxRetxThreshold in the LTE system), it is determined that the radio link environment is not good. Accordingly, a Radio Link Failure (RLF) is declared, and the terminal performs a procedure for reconfiguring a connection to a corresponding base station (a main base station or a secondary base station).

Fig. 2 illustrates the operation proposed by the present disclosure in the case where the number of RLC retransmissions reaches a maximum.

If the packet transmitted by the RLC device reaches the maximum number of RLC retransmissions (when the retxcount value reaches maxRetxThreshold in the LTE system) in S201, it may be determined whether a cell used by a corresponding logical channel corresponding to the RLC device is defined in S202.

As in the embodiment of fig. 1, if the corresponding logical channel can transmit data in a certain cell or cells, instead of in each cell, only the cells used by the corresponding logical channel may be released/deleted or deactivated in S203. In this case, RLF is not declared and RLF operations are not performed. On the other hand, if the corresponding logical channel can transmit data in each activated cell, RLF may be declared in S204.

The terminal may inform the base station that only cells used by the corresponding channel are released/deleted or deactivated. At this time, the base station may be notified by a different cell instead of the cell corresponding to the RLC device that has reached the maximum number of RLC retransmissions. According to an embodiment, an RLC device that has reached the maximum number of RLC retransmissions may request another RLC device (PDCP device) connected to the same radio bearer to send a corresponding message.

According to the embodiment, it may also be determined in the base station or another network device to delete or deactivate only the cells used by the corresponding logical channels. In this case, the terminal may report the situation of the corresponding terminal to the base station to allow the base station to determine whether to delete or deactivate the cell used by the corresponding logical channel. In response to the report from the terminal, the base station may delete or deactivate the cell used by the corresponding logical channel.

The information to be provided to the base station may include an ID of a logical channel that has reached the maximum Number of retransmissions, a CC index to which the packet is transmitted, an SCell index, a cell ID, a Sequence Number (SN) of a corresponding packet, and the like.

An indicator (indicator) of a network node or a cell group may be included in the dual connection structure in order to accurately distinguish a logical channel, a CC index, an SCell index, a cell ID, and the like.

If the embodiment of fig. 2 is applied to the duplicate packet transmission structure of fig. 1, the operation may be performed as follows.

In the case of performing duplicate packet transmission, if the transmission is not completed even if the packet has been maximally transmitted in RLC1 or RLC2, it may not be necessary to re-establish (renew) the entire connection to the base station. For example, in a case where transmission is not completed even though a packet has been maximally transmitted in the RLC2, it may be determined that the radio links of the SCell3 and the SCell 4 are not good. Thus, only connections to SCell3 and SCell 4 may be released, and connections to PCell, SCell1, and SCell2 connected to RLC1 may remain unchanged.

Fig. 3 illustrates the operation proposed by the present disclosure in the case where the number of RLC retransmissions reaches a maximum.

If the packet transmitted by the RLC device reaches the maximum number of RLC retransmissions (when the retxcount value reaches maxRetxThreshold in the LTE system) in S301, it may be determined whether a cell used by a corresponding logical channel corresponding to the RLC device is defined in S302.

As in the embodiment of fig. 1, if the corresponding logical channel can transmit data in a certain cell or cells instead of in each cell and data cannot be transmitted in a PCell among the cells, only the cells used by the corresponding logical channel may be released/deleted or deactivated in S303. In this case, RLF is not declared and RLF operations are not performed. Even though the corresponding logical channel may transmit data in a certain cell or cells instead of in each cell, if the corresponding logical channel may transmit data in a PCell among the cells, RLF may be announced in S304.

In the embodiment of fig. 3, if the situation corresponds to S303, RLF is not declared and RLF operation is not performed. On the other hand, if the corresponding logical channel can transmit data in each activated cell, RLF can be declared.

The terminal may inform the base station of deletion, release, or deactivation of only cells used by the corresponding logical channel. At this time, the base station may be notified by a different cell instead of the cell corresponding to the RLC device that has reached the maximum number of RLC retransmissions. An RLC device that has reached the maximum number of RLC retransmissions according to an embodiment may request another RLC device (PDCP device) connected to the same radio bearer to send a corresponding message.

Whether only cells used by corresponding logical channels according to an embodiment are deleted or deactivated may be determined by the base station or another network device. In this case, the terminal may report the situation of the corresponding terminal to the base station to allow the base station to determine whether to delete or deactivate the cell used by the corresponding logical channel. In response to the report from the terminal, the base station may delete or deactivate the cell used by the corresponding logical channel.

An indicator for a network node or cell group may be included in the dual connection structure in order to accurately distinguish a logical channel, a CC index, a SCell index, a cell ID, and the like.

If the embodiment of fig. 3 is applied to the duplicate packet transmission structure of fig. 1, the operation may be performed as follows. In the case where the duplicate packet transmission of fig. 1 is performed, in the case where the transmission is not completed even though the packet has been maximally transmitted in RLC1 or RLC2, it may not be necessary to re-establish the entire connection to the base station. For example, in the case where transmission is not completed even if a packet has been maximally transmitted in the RLC2, it is determined that the radio links of the SCell3 and the SCell 4 are not good. Thus, only connections to SCell3 and SCell 4 may be released, and connections to PCell connected to RLC1, SCell1, and SCell2 may remain unchanged.

However, in case that transmission is not completed even though a packet has been maximally transmitted in RLC1, RLF is declared because RLC1 is configured to transmit data using Pcell and an operation defined after RLF will be performed.

Fig. 4 illustrates an embodiment of operations in the case where RLF occurs in an environment limited by which cells the logical channel can use in the duplicated packet transmission structure.

If, in the embodiment of fig. 4, RLF occurs in RLC2 corresponding to logical channel 2, RLC2 may be reset. In another embodiment, logical channel 2 may delete or deactivate SCell3 and SCell 4 through which packets are transmitted. However, this is not limited to application only to duplicate packet transmission structures, and may equally apply in environments limited to which cells the logical channels may be used.

Fig. 5 illustrates one embodiment of operation in the case where a packet reaches the maximum number of RLC retransmissions (when the rettx _ COUNT value reaches maxRetxThreshold in an LTE system).

The terminal may notify the base station that the number of RLC retransmissions has reached a maximum. In the embodiment of fig. 5, a message is sent reporting that the number of transmissions has reached a maximum. The message may be sent to the base station through a different cell than the cell corresponding to the RLC device that has reached the maximum number of retransmissions.

An RLC device that has reached the maximum number of RLC retransmissions according to an embodiment may request another RLC device (PDCP device) connected to the same radio bearer to send a corresponding message. The information to be provided to the base station may include an ID of a logical channel that has reached the maximum number of retransmissions, a CC index to which the packet is transmitted, an SCell index, a cell ID, a Sequence Number (SN) of a corresponding packet, and the like.

After transmitting the message, the transmitter may reset the corresponding logical channel or RLC device. After sending the message, the receiver may reset the corresponding logical channel or RLC device.

The reset of the corresponding logical channel or RLC device according to an embodiment may be determined by the base station or another network device. In this case, the base station may instruct the corresponding logical channel or RLC device to be reset after the number of report transmissions has reached the maximum.

In an embodiment, the CC index, the SCell index, and the cell ID included in the message reporting that the number of transmission times has reached the maximum, or the CC or cell corresponding to at least one of them may also be deleted or deactivated. The procedure of fig. 5 may also be applied only to logical channels that transmit packets without using the Pcell.

Fig. 6 shows another embodiment of the operation in the case where the packet has reached the maximum number of RLC retransmissions (when the rettx _ COUNT value has reached maxRetxThreshold in the LTE system).

The terminal may notify the base station that the number of RLC retransmissions has reached a maximum. In the embodiment of fig. 6, a message is sent reporting that the number of transmissions has reached a maximum. The message may be sent to the base station through a different cell than the cell corresponding to the RLC device that has reached the maximum number of RLC retransmissions. An RLC device that has reached the maximum number of RLC retransmissions according to an embodiment may request another RLC device (PDCP device) connected to the same radio bearer to send a corresponding message. In this case, the information to be provided to the base station may include an ID of a logical channel that has reached the maximum number of retransmissions, a CC index to which the packet is transmitted, an SCell index, a cell ID, a Sequence Number (SN) of a corresponding packet.

After transmitting the message, the transmitter may perform processing as if the packet having reached the maximum number of retransmissions has been completely transmitted, and may continue the transmission/reception operation. After transmitting the message, the receiver can perform processing as if a packet that has reached the maximum number of retransmissions has been successfully received, and can continue the transmission/reception operation.

According to the embodiment, whether to perform processing as if the packet having reached the maximum number of retransmissions has been completely transmitted may also be determined by the base station or another network device. In this case, after the number of reported transmissions has reached a maximum, the base station may provide instructions to perform processing as if the corresponding packet had been completely transmitted.

Further, in an embodiment, the CC index, the SCell index, and the cell ID included in the message reporting that the number of transmission times has reached the maximum, or the CC or the cell corresponding to at least one of them may be deleted or deactivated. The procedure of fig. 6 may also be applied only to logical channels that transmit packets without using the Pcell.

Fig. 7 illustrates an embodiment in which a cell used by a logical channel to transmit a packet is changed according to duplicate packet activation and deactivation.

If duplicate packet transmission is activated, each of the RLC device and the logical channel corresponding thereto may have a defined cell through which packets may be transmitted. In the embodiment of fig. 7, logical channel 1701 may transmit packets using PCell 711, SCell 1712, and SCell 2713, and logical channel 2702 may transmit packets using SCell 3714 and SCell 4715. However, in the case where only one RLC device can perform packet transmission due to deactivation of packet duplication, it may not be necessary to limit a cell that can be used to transmit a packet with respect to a logical channel.

If packet duplication is deactivated in the embodiment of fig. 7, only the RLC 1701 can perform packet transmission. In this case, logical channel 1 may transmit a packet using all of PCell 711, SCell 1712, SCell 2713, SCell 3714, and SCell 4715. That is, packet transmission may be performed through all activated cells.

If RLC2 has remaining packets that should be transmitted and the corresponding packets cannot be destroyed, RLC2 may also perform the transmission of the corresponding remaining packets. In this case, packet transmission may be performed through all activated cells in the same manner as in RLC 1.

Fig. 8 illustrates an embodiment of operations in the case where duplicate packet transmission is activated.

Duplicate packet transmission may be activated by a Medium Access Control (MAC) Control Element (CE), a Radio Resource Control (RRC) message, a PDCP Control PDU, and the like. In S801, the terminal may receive an instruction for activating duplicate packet transmission through these messages. In S802, there may be no cell in an active state among cells that may be used by logical channels connected to the duplicate transport bearer. For example, in the embodiment of fig. 7, SCell3 and SCell 4 may be in a deactivated state when duplicate packet transmission is activated.

In this case, at least one cell among cells that can be used by logical channels connected to the duplicate transmission bearer may be activated in S803 to start duplicate packet transmission in S804. For example, in the embodiment of fig. 7, an operation of activating at least one cell of SCell3 and SCell 4 is performed.

Fig. 9 illustrates an embodiment of operations in the case where duplicate packet transmission is activated.

Duplicate packet transmission may be activated by MAC CE, RRC message, PDCP control PDU, etc. In S901, the terminal can receive an instruction for activating duplicate packet transmission through these messages. In S902, there may be no cell in an active state among cells that may be used by logical channels connected to the duplicate transport bearer. For example, in the embodiment of fig. 7, SCell3 and SCell 4 may be in a deactivated state when duplicate packet transmission is activated.

In this case, since copy transmission cannot be performed, a packet copy deactivation state may be maintained in S903. Thereafter, in the case where at least one of the cells that can be used by the logical channels connected to the duplicate transmission bearer is activated, duplicate packet transmission may be performed in S904.

Fig. 10 illustrates an embodiment of operations in a case where an instruction for SCell deactivation is received when duplicate packet transmission is activated.

In a state where duplicate packet transmission is performed in S1001, an instruction for SCell deactivation may be received through the MAC CE in S1002. However, the SCell may not be limited to the deactivated state, but may be applied to a state in which the SCell is released.

In S1003, the terminal that has received the instruction for SCell deactivation deactivates the corresponding SCell. Thereafter, it may be checked in S1004 whether there is an active cell among cells that may be used by logical channels connected to the duplicate transport bearer. If there is no cell in the active state in the logical channel, duplicate packet transmission may be deactivated or duplicate packet transmission logical channels of cells having no packet transmitted therethrough may be deleted in S1005. Otherwise, the duplicate packet transmission is continued in S1006.

Fig. 11 illustrates an embodiment in which the bearer and user plane protocol stacks are configured in a non-standalone (NSA) architecture including LTE new radio (LTE-NR) coexisting therein. An LTE base station/terminal may be referred to as a Master Node (MN), and an NR base station/terminal may be referred to as a Secondary Node (SN).

In addition, the bearers may include Master Cell Group (MCG) bearers, MCG split bearers, Secondary Cell Group (SCG) bearers, and SCG split bearers. The Bearer may be applied to both a Data Radio Bearer (DRB) and a Signaling Radio Bearer (SRB) that transmits Data.

Fig. 11(a) shows an example of LTE and NR protocol stacks that remain unchanged.

Fig. 11(b) shows an example of MCG split bearer using NR-PDCP in PDCP. The difference between the MCG split bearer and the SCG split bearer is eliminated internally in the terminal.

Fig. 11(c) shows an example of MCG bearer using NR-PDCP in PDCP. In the embodiment of fig. 11(c), NR-PDCP is used for all bearers in the NSA structure.

FIG. 11(d) shows an example of a split bearer using NR-PDCP and NR-RLC in PDCP and RLC, respectively. The difference between the MCG split bearer and the SCG split bearer is eliminated internally in the terminal.

The embodiment of fig. 11(e) shows an example where NR-PDCP and NR-RLC are used for all bearers in the NSA structure.

The SCG/SCG split bearer using a secondary Node (NR) base station/terminal as a PDCP anchor always uses NR-PDCP. However, an MCG/MCG split bearer using a primary node (LTE) base station/terminal as a PDCP anchor may need to determine which PDCP to use. In this case, the base station may notify the terminal of the protocol stack to be applied at the bearer establishment. Otherwise, in case of MCG split bearer or MCG bearer using the master node as anchor point, NR-PDCP may be used by default. Meanwhile, NR-PDCP may also always be used in NSA architecture where the primary node is LTE and the secondary node is NR.

Fig. 12 shows an example in which a base station transmits a PDCP-Config message to a terminal. The PDCP-Config may indicate which PDCP version is to be used by the PDCP layer among the NR-PDCP and the LTE-PDCP. Similarly, RLC-Config may also be sent from the base station to the terminal. The RLC-Config may also indicate which RLC version to use among the NR-RLC and the LTE-RLC.

In an embodiment, the base station may further inform the terminal whether the PDCP anchor of the base station is the primary node or the secondary node. In addition, the PDCP-Config may include information on: whether to apply integrity protection to a bearer using a host node as an anchor point; which integrity protection algorithm to apply; which algorithm of the security key to apply; whether to generate a security key using the KeNB and the S-KeNB; and so on.

Fig. 13 is an example showing a terminal implementation structure in the case where the MCG split bearer applies NR-PDCP.

If the MCG detached bearer (MCG) uses NR-PDCP, the MCG detached bearer has no structural difference from the SCG detached bearer (SCG), and thus a PDCP anchor can be implemented as an NR modem in the terminal.

Fig. 14 illustrates a method for generating a security key in an NSA architecture.

In the NSA architecture, the primary and secondary nodes may have KeNB and S-KeNB values, respectively, and may generate security keys, such as KRRCint, KRRCenc, KUPenc, etc., by applying these values to a key derivation algorithm. There may be LTE key derivation algorithms and NR key derivation algorithms in the NSA architecture. The key may be generated using a combination of fig. 14(a) to 14 (d). It is assumed that the KUPenc key is generated in fig. 14(a) to 14(d), but the combination may be equally applied to other security keys.

Fig. 14(a) shows an embodiment of generating KUPenc by applying KeNB to the LTE key derivation algorithm.

Fig. 14(b) shows an embodiment of generating KUPenc by applying KeNB to the NR key derivation algorithm.

Fig. 14(c) shows an embodiment of generating KUPenc by applying S-KeNB to LTE key derivation algorithm.

Fig. 14(d) shows an embodiment of generating KUPenc by applying S-KeNB to NR key derivation algorithm.

In a bearer using the primary node of the NSA structure as a PDCP anchor point (bearer terminated by MN), the security key generation method shown in fig. 14 may be applied using at least one of the following methods:

applying KeNB to an LTE key derivation algorithm to generate KUPenc, and applying KUPenc to both NR-PDCP and LTE-PDCP;

applying KeNB to NR key derivation algorithm to generate KUPenc, and applying KUPenc to both NR-PDCP and LTE-PDCP;

applying KeNB to the LTE key derivation algorithm to generate KUPenc1, KUPenc1 to the LTE-PDCP, and KeNB to the NR key derivation algorithm to generate KUPenc2, and KUPenc2 to the NR-PDCP;

applying KeNB to the LTE key derivation algorithm to generate KUPenc1, KUPenc1 to the LTE-PDCP, and S-KeNB to the NR key derivation algorithm to generate KUPenc2, and KUPenc2 to the NR-PDCP;

applying KeNB to the LTE key derivation algorithm to generate KUPenc1, KUPenc1 to the LTE-PDCP, and S-KeNB to the LTE key derivation algorithm to generate KUPenc2, and KUPenc2 to the NR-PDCP;

applying KeNB or S-KeNB to LTE key derivation algorithm to generate KUPenc, and applying KUPenc to both NR-PDCP and LTE-PDCP, wherein the base station or network provides notification of whether KeNB or S-KeNB is used;

applying KeNB or S-KeNB to NR key derivation algorithm to generate KUPenc, and applying KUPenc to both NR-PDCP and LTE-PDCP, wherein the base station or network provides notification of whether KeNB or S-KeNB is used;

applying KeNB or S-KeNB to LTE or NR key derivation algorithm to generate KUPenc, and applying KUPenc to both NR-PDCP and LTE-PDCP, wherein the base station or network provides notification of whether KeNB or S-KeNB is used, and the base station or network provides notification of whether LTE or NR key derivation algorithm is used; and

applying KeNB or S-KeNB to LTE or NR key derivation algorithm to generate KUPenc, and applying KUPenc to both NR-PDCP and LTE-PDCP, wherein a default value for whether KeNB or S-KeNB is used may be pre-configured, and a default value for whether LTE or NR key derivation algorithm is used may be pre-configured.

The NR-PDCP may also apply integrity protection to the DRB. Integrity protection may be configured if the primary node (LTE) supports NR-PDCP. In an embodiment, in case the split bearer using the primary node as PDCP anchor uses NR-PDCP, the integrity protection may be released by default. In another embodiment, in the case where the split bearer using the primary node as a PDCP anchor uses NR-PDCP, it may be determined whether integrity protection is supported. In another embodiment, where the split bearer using the primary node as the PDCP anchor uses NR-PDCP, the secondary node may be requested to determine whether integrity protection is supported. In another embodiment, in case the split bearer using the primary node as PDCP anchor uses NR-PDCP, whether or not integrity protection is supported may be configured by PDCP-Config.

Fig. 15 shows an example in which the integrity check may be determined as a security attack.

In the case of the split bearer in fig. 15(a), the PDCP device may be connected to a plurality of RLC devices, and in the case of receiving the same packet from the RLC device, if duplicate packet transmission is not in an active state, this may be determined as a security attack.

In the case where the same packet is received from one RLC device in fig. 15(b), this may be determined as a security attack regardless of whether duplicate packet transmission is activated.

Fig. 16 illustrates an embodiment of a method of operation for performing integrity checking in a bearer that does not allow duplicate packet transmission. The corresponding operation may also be applied to the case where duplicate packet transmission is deactivated. The method of operation of fig. 16 may be applicable to both SRBs and DRBs.

If integrity protection of a certain bearer is configured in S1601, it may be identified in S1603 whether the same packet has been received whenever a packet is received in S1602. In this case, the "same packet" may be a packet having the same PDCP count.

If the same packet has been received, this may be determined as a security attack in a state where duplicate packet transmission is not allowed. In this case, the terminal may report to a higher layer or may report about the attack to the base station in S1604. In addition, a connection reconfiguration procedure may be performed based on the report.

On the other hand, if the same packet has not been received, the received data may be processed in S1605.

Fig. 17 illustrates a method of operation for performing integrity checking in a bearer that allows duplicate packet transmission. The corresponding operation may not be applied to the case where duplicate packet transmission is deactivated. The method of operation of fig. 17 may be applicable to both SRBs and DRBs that allow duplicate packet transmission.

If integrity protection of a certain bearer is configured in S1701, it can be recognized in S1703 whether the same packet has been received whenever the packet is received in S1702. In this case, the "same packet" may be a packet having the same PDCP count.

If the same packet has been received and received from the same RLC device, this may be determined as a security attack. In this case, the terminal may report to a higher layer or may report to the base station about the attack in S1704. In addition, a connection reconfiguration procedure may be performed based on the report.

This may be determined as a normal duplicate packet transmission procedure if the same packet is received from a different RLC device. Accordingly, the corresponding packet is discarded in S1705, and then the data processing (receiving) process may continue in S1706.

Referring to fig. 18, the terminal may include a transceiver 1810, a controller 1820, and a memory 1830. In this disclosure, a controller may be defined as a circuit, an application specific integrated circuit, or at least one processor.

The transceiver 1810 may transmit and receive signals with another network entity. For example, the transceiver 1810 may receive system information from a base station and may receive a synchronization signal or a reference signal.

The controller 1820 may control the overall operation of the terminal according to embodiments presented in the present disclosure. For example, the controller 1820 may control the signal flow between blocks to perform operations according to the flowcharts described above.

The memory 1830 may store at least one of information transmitted and received by the transceiver 1810 and information generated by the controller 1820.

Referring to fig. 19, the base station may include a transceiver 1910, a controller 1920, and a memory 1930. In this disclosure, a controller may be defined as a circuit, an application specific integrated circuit, or at least one processor.

The transceiver 1910 may transmit and receive signals with another network entity. For example, the transceiver 1910 may receive system information from a terminal and may receive a synchronization signal or a reference signal.

The controller 1920 may control the overall operation of the base station according to the embodiments proposed by the present disclosure. For example, the controller 1920 may control the signal flow between the blocks to perform operations according to the above-described flow diagrams.

The memory 1930 may store at least one of information transmitted and received by the transceiver 1910 and information generated by the controller 1920.

The embodiments disclosed in the specification and drawings are only for the purpose of easily describing and assisting a comprehensive understanding of the present disclosure, and do not limit the scope of the present disclosure. Therefore, it should be understood that all modifications and changes or forms of modifications and changes derived from the technical idea of the present disclosure, other than the embodiments disclosed herein, fall within the scope of the present disclosure.

Claims

1. A method of a terminal in a wireless communication system, the method comprising:

performing Protocol Data Convergence Protocol (PDCP) duplication to transmit a same PDCP Protocol Data Unit (PDU) to a base station through a first logical channel and a second logical channel;

retransmitting the PDCP PDU to the base station if a request for retransmission of the PDCP PDU transmitted through a second logical channel is received; and

receiving information indicating deactivation of the PDCP duplication from the base station if a number of retransmission times of PDCP PDUs becomes equal to or greater than a preconfigured number.

2. The method of claim 1, further comprising:

transmitting a report to the base station, wherein the report provides a notification that the number of retransmissions of the PDCP PDU is equal to or greater than a preconfigured number,

wherein information indicating deactivation of the PDCP duplication is received in response to the report, and

wherein, if the PDCP duplication is deactivated, restriction on at least one cell mapped to each of the first and second logical channels is released to transmit the PDCP PDUs.

3. The method of claim 1, further comprising:

receiving configuration information of a bearer corresponding to each of the first and second logical channels from the base station,

wherein the configuration information of the bearer includes PDCP configuration information of the bearer and security information applied to the bearer.

4. The method of claim 1, wherein the first logical channel corresponds to a first base station and the second logical channel corresponds to a second base station,

wherein the first base station and the second base station are connected to a first core network, and

wherein a bearer corresponding to each of the first logical channel and the second logical channel is configured using the NR-PDCP.

5. A method of a base station in a wireless communication system, the method comprising:

sending a message to a terminal, wherein the message indicates activation of Protocol Data Convergence Protocol (PDCP) duplication for sending a same PDCP Protocol Data Unit (PDU) over a first logical channel and a second logical channel;

requesting retransmission of the PDCP PDU transmitted through the second logical channel to the terminal;

receiving a report from the terminal, wherein the report provides a notification that the number of retransmissions of the PDCP PDU is equal to or greater than a preconfigured number; and

transmitting information indicating deactivation of the PDCP duplication to the terminal.

6. The method of claim 5, wherein in response to receiving the report, restriction on at least one cell mapped to each of the first and second logical channels is removed in order to transmit the PDCP PDU.

7. The method of claim 5, further comprising:

transmitting configuration information of a bearer corresponding to each of the first and second logical channels to the terminal,

8. A terminal in a wireless communication system, the terminal comprising:

a transceiver; and

a controller configured to perform Protocol Data Convergence Protocol (PDCP) duplication to transmit same PDCP Protocol Data Units (PDUs) to a base station through a first logical channel and a second logical channel, control the transceiver to retransmit the PDCP PDUs to the base station if a request for retransmission of the PDCP PDUs transmitted through the second logical channel is received from the base station, and control the transceiver to receive information indicating deactivation of the PDCP duplication from the base station if a PDCP PDU retransmission number becomes a preconfigured number.

9. The terminal of claim 8, wherein the controller controls the transceiver to transmit a report to the base station, wherein the report provides a notification that the number of retransmissions of the PDCP PDU is equal to or greater than a preconfigured number,

wherein, if the PDCP duplication is deactivated, a restriction on at least one cell mapped to each of the first and second logical channels is released to transmit the PDCP PDUs.

10. The terminal of claim 8, wherein the controller controls the transceiver to receive configuration information of a bearer corresponding to each of the first and second logical channels from the base station, and

11. The terminal of claim 5, wherein the first logical channel corresponds to a first base station and the second logical channel corresponds to a second base station,

wherein a bearer corresponding to each of the first logical channel and the second logical channel is configured as NR-PDCP.

12. A base station in a wireless communication system, the base station comprising:

a transceiver; and

a controller configured to transmit a message to a terminal, wherein the message indicates activation of Protocol Data Convergence Protocol (PDCP) duplication for transmitting the same PDCP Protocol Data Units (PDUs) through a first logical channel and a second logical channel, request retransmission of the PDCP PDUs transmitted through the second logical channel to the terminal, receive a report from the terminal, wherein the report provides notification that the number of retransmission of the PDCP PDUs is equal to or greater than a preconfigured number, and control the transceiver to transmit information indicating deactivation of the PDCP duplication to the terminal.

13. The base station of claim 12, wherein the controller is configured to release restriction on at least one cell mapped to each of the first and second logical channels in response to receiving the report, so as to transmit the PDCP PDU.

14. The base station according to claim 12, wherein the controller is configured to control the transceiver to transmit configuration information of a bearer corresponding to each of the first and second logical channels to the terminal,

15. A terminal method according to claim 3, in which the report includes an ID of the first logical channel.